#include <stdio.h>
int main(void)
{
	// 读
	FILE *f = popen("cat /etc/passwd","r");
	char str[1024] = {'\0'};
	while(NULL != fgets(str,1024,f))
	{
		// printf("%s",str);
	}
	pclose(f);
	// 写
	f = popen("wc -l","w");
	fprintf(f,"/etc/passwd\n/etc/shadow");
	pclose(f);
	return 0;
}
